LTC2952

1

2952fa

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Controller with Supervisor

three main functions: pushbutton on/off control of system

power, ideal diode PowerPath controllers and system moni-

toring. The LTC2952’s pushbutton input, which provides

on/off control of system power, has independently adjust-

able ON and OFF debounce times. A simple microprocessor

interface involving an interrupt signal allows for proper

system housekeeping prior to power-down.

The ideal diode PowerPath controllers provide automatic

low loss switchover between two DC sources by regulating

two external P-channel MOSFETs to have a small 20mV

forward drop.

High reliability systems may utilize the LTC2952’s monitor-

ing features to ensure system integrity. These features in-

clude: power-fail, voltage monitoring and μP watchdog.

The LTC2952 operates over a wide operating voltage range

to accommodate a large variety of input power supplies. The

part’s combination of low 20mV external MOSFET regula-

tion and very low standby current matches battery powered

and power conscious application requirements.

Pushbutton Controller with Automatic Switchover Between Adapter and Battery

n

Pushbutton On/Off Control

n

Automatic Low Loss Switchover Between DC

Sources

n

Wide Operating Voltage Range: 2.7V to 28V

n

Low 25μA Shutdown Current

n

Guaranteed Threshold Accuracy: ±1.5% of

Monitored Voltage Over Temperature

n

Adjustable Pushbutton On/Off Timers

n

Simple Interface Allows Graceful μP Shutdown

n

Extendable Housekeeping Wait Time Prior to

Shutdown

n

200ms Reset Delay and 1.6s Watchdog Timeout

n

±8kV HBM ESD on PB Input

n

20-pin TSSOP and QFN (4mm

× 4mm) Packages

n

Desktop and Notebook Computers

n

Portable Instrumentations

n

Cell Phones, PDA and Handheld Computers

n

Servers and Computer Peripherals

n

Battery Backup Systems

Ideal Diode vs Schottky Diode

Forward Voltage Drop

LTC2952

LT1767-2.5

SHDN

PFI

G1

VM

RST

INT

G1STAT

PFO

KILL

WDE

G2

V1

V2

M1

M2

PB

EN

VS

ONT

GND OFFT

2952 TA01

ADAPTER, 3V TO 25V

2.5V

12V BATTERY

Si6993DQ

Si6993DQ

μP

365k

511k

100k

*68nF

*OPTIONAL

*22nF

100k

1k

1k

1k

10k

D2

D3

D1

FORWARD VOLTAGE (V)

0.02

0.50

2952 TA01b

0

1

CONSTANT

VOLTAGE

SCHOTTKY

DIODE

IDEAL

DIODE

CONSTANT

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks

are the property of their respective owners.